Vehicle-mounted control devices

Abstract

To suppress frequent guiding given so as press a brake pedal when a regenerative brake force falls on the basis of the state of a power storage device.SOLUTION: When a regenerable torque obtained through regenerative driving of an electric motor becomes equal to or higher than a prescribed threshold value, prescribed notification is executed, a message about the execution of the prescribed notification is stored as history, and permitted maximum input power inputtable to a power storage device when the notification is executed is stored as control input power. If there is history of messaging about the execution of the prescribed notification, the notification is executed again when the regenerable torque is equal to or higher than the threshold value and when an absolute value of the permitted maximum input power is less than that of the control input power.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle control device, and more particularly to an in-vehicle control device mounted on an electric vehicle.

Background Art

[0002] Conventionally, as this type of in-vehicle control device, when the difference obtained by subtracting the regenerative braking amount calculated from the operation state of the accelerator pedal from the upper limit amount of regeneration calculated from the state of charge of the battery is less than a predetermined amount, a guidance is proposed to prompt stepping on the brake pedal, such as "Please step on the brake" (see, for example, Patent Document 1). In this device, the discomfort of the driver associated with the pedal switching operation when the regenerative braking force cannot be obtained is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described device, when the regenerative braking force decreases based on the state of charge of the battery, a guidance prompt to step on the brake pedal may be frequently given. Such frequent notification of the guidance causes annoyance to the driver and passengers.

[0005] The main object of the in-vehicle control device of the present disclosure is to suppress the frequent guidance to prompt stepping on the brake pedal when the regenerative braking force decreases based on the state of the power storage device.

Means for Solving the Problems

[0006] The in-vehicle control device of the present disclosure has taken the following means to achieve the above main object.

[0007] The in-vehicle control device disclosed herein is An on-board control device mounted on an electric vehicle, comprising an electric motor for propulsion and a power storage device that exchanges power with the electric motor, When the regenerative torque obtained by the regenerative drive of the electric motor reaches a predetermined threshold or higher, a predetermined notification is issued, and the fact that the predetermined notification was issued is recorded in the history, and the maximum permissible input power that can be input to the energy storage device at the time the predetermined notification was issued is stored as the control input power. If there is a record of the predetermined notification being given, the predetermined notification is given again when the regenerative torque is equal to or greater than the predetermined threshold and the absolute value of the allowable maximum input power is less than the absolute value of the control input power. It is characterized by the following:

[0008] In the in-vehicle control device of this disclosure, a predetermined notification is issued when the regenerative torque obtained by the regenerative drive of the electric motor reaches a predetermined threshold or higher (the absolute value of the regenerative torque is less than or equal to the predetermined threshold), and this fact is recorded in the history. The maximum allowable input power that can be input to the energy storage device at the time the predetermined notification is issued is stored as the control input power. When there is a history of a predetermined notification being issued, a predetermined notification is issued again when the regenerative torque is above the predetermined threshold and the absolute value of the maximum allowable input power is less than the absolute value of the control input power. That is, a predetermined notification is issued again when the regenerative torque is above the predetermined threshold (the absolute value of the regenerative torque is less than or equal to the predetermined threshold) and the maximum allowable input power is greater than (smaller in absolute value) the control input power. Here, the output torque of the electric motor is a positive value, and the regenerative torque of the electric motor is a negative value. Furthermore, the power output from the energy storage device (discharge power) is a positive value, and the power input to the energy storage device (charging power) is a negative value. In this disclosure, if there is a history of a predetermined notification being given, even if the regenerative torque is above a predetermined threshold (the absolute value of the regenerative torque is below the predetermined threshold), if the allowable maximum input power is smaller than the control input power (larger in absolute value), the predetermined notification will not be given again. This makes it possible to suppress the frequent giving of predetermined notifications when the regenerative braking force decreases based on the state of the energy storage device.

[0009] In the in-vehicle control device of this disclosure, the control input power may be subject to an upper limit guard by the allowable maximum input power. That is, when the control input power becomes smaller than the allowable maximum input power (i.e., its absolute value as a negative value becomes larger), it is replaced by the allowable maximum input power.

[0010] In the in-vehicle control device of this disclosure, the predetermined notification includes a notification prompting the driver to apply the brakes. The predetermined threshold includes one set based on the shift position. The history of predetermined notifications may be cleared when the system is started or when the absolute value of the maximum allowable input power of the energy storage device exceeds a predetermined value. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows a schematic configuration of an electric vehicle 20 equipped with an in-vehicle control device as an embodiment of the present disclosure. [Figure 2] This flowchart shows an example of a predetermined notification process performed by the electronic control unit 30. [Figure 3] This is an explanatory diagram showing an example of the time variation of a predetermined notification, a notification history flag Frec, a regenerative torque Tm, and a control limit Winc when a predetermined notification process of the embodiment is executed. [Modes for carrying out the invention]

[0012] Next, embodiments of the present disclosure will be described. Figure 1 is a schematic diagram showing the configuration of an electric vehicle 20 equipped with an in-vehicle control device as an embodiment of the present disclosure. The electric vehicle 20 comprises a motor 22, an inverter 23, a battery 24, and an electronic control unit 30.

[0013] The motor 22 is configured, for example, as a synchronous regenerative motor. The rotor of the motor 22 is connected to a drive shaft 26 which is connected to drive wheels 28a and 28b via a differential gear 27. The motor 22 is driven by the three-phase AC power applied by the inverter 23, which is converted from DC power from the battery 24. The motor 22 also functions as a generator through regenerative control, generating electricity using the rotational power of the drive shaft 26 and charging the battery 24 via the inverter 23. The battery 24 is configured as a well-known lithium-ion secondary battery or nickel-metal hydride secondary battery.

[0014] The electronic control unit 30, although not shown, is configured as a microcomputer centered around a CPU. The electronic control unit 30 receives signals from various sensors via input ports. For example, the electronic control unit 30 receives the ignition signal from the ignition switch 42, the shift position SP from the shift position sensor 44 which detects the position of the shift lever 43, the accelerator opening Acc from the accelerator pedal position sensor 46 which detects the amount the accelerator pedal 45 is pressed, the brake position BP from the brake pedal position sensor 48 which detects the amount the brake pedal 47 is pressed, and the vehicle speed V from the vehicle speed sensor 49. The electronic control unit 30 also receives the rotational position θ from the rotational position sensor (not shown) which detects the rotational position of the motor 22, the battery voltage Vb from the voltage sensor (not shown) attached to the output terminal of the battery 24, and the battery current Ib from the current sensor (not shown) attached to the output terminal of the battery 24. Furthermore, the electronic control unit 30 also receives the switch signal SW from the changeover switch 50 which switches the various displays of the display device 52. The shift positions include a parking position (P position), a neutral position (N position), a forward drive position (D position), a reverse drive position (R position), and a brake position (B position). The brake position (B position) is the position in which the braking torque applied to the vehicle when the accelerator is released is smaller (in absolute value, larger) than that of the forward drive position (D position). In this embodiment, the torque is set to a positive value when the motor 22 outputs drive torque, and to a negative value when the motor 22 outputs regenerative torque. Also, the current and power when discharging from the battery 24 are set to positive values, and the current and power when charging the battery 24 are set to negative values.

[0015] The electronic control unit 30 outputs various control signals via its output ports. For example, the electronic control unit 30 outputs a display control signal to the display device 52. The electronic control unit 30 also outputs a switching control signal for switching a switching element (not shown) to the inverter 23 for driving the motor 22, and a drive control signal to the system main relay 25 installed near the battery 24.

[0016] The electronic control unit 30 calculates the rotational speed Nm of the motor 22 based on the rotational position θ detected by a rotational position sensor (not shown) that detects the rotational position of the motor 22, and calculates the state of charge (SOC) of the battery 24 based on the battery voltage Vb and battery current Ib. The state of charge (SOC) is the ratio of the remaining capacity to the total capacity of the battery 24. The electronic control unit 30 also calculates the output limit Wout, which is the maximum allowable power that can be output from the battery 24, and the input limit Win, which is the maximum allowable power that can be input (charged) to the battery 24, based on the state of charge (SOC) of the battery 24 and the temperature Tb of the battery 24.

[0017] Next, we will describe the operation of the electric vehicle 20 of the embodiment, in particular, the operation when a predetermined notification is performed to prompt the driver to press the brake pedal 47 because the State of Charge (SOC) of the battery 24 has increased and the input limit Win has increased (in absolute value, decreased). Figure 2 is a flowchart showing an example of a predetermined notification process performed by the electronic control unit 30. This predetermined notification process is performed repeatedly at predetermined intervals.

[0018] When the predetermined notification process is executed, the electronic control unit 30 first inputs the shift position SP, the regenerative torque Tm by the motor 22, and the input limit Win of the battery 24 (step S100). The shift position SP is input as the one detected by the shift position sensor 44. The regenerative torque Tm is input as the one obtained based on the vehicle speed V and the input limit Win of the battery 24 (Tm = k·Win / V). Here, k is a conversion coefficient. The input limit Win of the battery 24 is input as the one calculated based on the power storage ratio SOC of the battery 24, the temperature Tb of the battery 24, and the like.

[0019] Next, it is determined whether the regenerative torque Tm is greater than or equal to the threshold value Tref(SP) based on the shift position SP (step S110). The threshold value Tref(SP) is the braking torque (negative torque) to be applied to the vehicle when the accelerator is off, and a smaller value (larger in absolute value) is used when the shift position SP is in the B position than when the shift position SP is in the D position. Since the regenerative torque Tm is a negative value and the threshold value Tref(SP) is also a negative value, the process in step S110 is synonymous with the process of determining whether the absolute value of the regenerative torque Tm is less than or equal to the absolute value of the threshold value Tref(SP).

[0020] When it is determined in step S110 that the regenerative torque Tm is less than the threshold value Tref(SP), it is determined whether the notification history flag Frec has a value of 1 (step S170). When it is determined that the notification history flag Frec has a value of 0, this process ends. The notification history flag Frec is set by this predetermined notification process, and a value of 0 is set as the initial value at the time of system startup. Now, considering immediately after the system startup, it is determined in step S110 that the regenerative torque Tm is less than the threshold value Tref(SP), and it is determined in step S170 that the notification history flag Frec has a value of 0. Therefore, this predetermined notification process ends without doing anything in particular.

[0021] When it is determined in step S110 that the regenerative torque Tm is greater than or equal to the threshold value Tref(SP) (the absolute value of the regenerative torque Tm is less than or equal to the absolute value of the threshold value Tref(SP)), it is determined whether the notification history flag Frec has a value of 0 (step S120). Considering the case where it is determined for the first time after the system is started that the regenerative torque Tm is greater than or equal to the threshold value Tref(SP), since the notification history flag Frec has the initial value of 0, in step S120, it is determined that the notification history flag Frec has a value of 0. In this case, in order to indicate the history of the predetermined notification, the value 1 is set in the notification history flag Frec (step S130), and a predetermined notification is performed, such as displaying a message prompting the depression of the brake pedal 47, such as "The deceleration is decreasing. Please step on the brake pedal." on the display device 52 (step S150), and the input limit Win of the battery 24 at that time is set to the control limit Winc (step S160).

[0022] Subsequently, it is determined whether the notification history flag Frec has a value of 1 (step S170). Considering immediately after the processing of steps S130, S150, and S160 is executed, in step S170, it is determined that the notification history flag Frec has a value of 1, and a minimum select process is performed to set the smaller of the control limit Winc and the input limit Win to the new control limit Winc (step S180). Since the control limit Winc and the input limit Win are negative values, the processing in step S180 is a process of upper limit guarding the control limit Winc with the input limit Win.

[0023] Then, it is determined whether the input limit Win of the battery 24 is less than the predetermined value Wref (step S190). The predetermined value Wref can be a value of the input limit Win of the battery 24 that does not need to consider the decrease in the deceleration. That is, step S190 determines whether the state such as the state of charge SOC of the battery 24 is in a state where the decrease in the deceleration does not need to be considered. When it is determined that the input limit Win of the battery 24 is less than the predetermined value Wref, the notification history flag Frec is reset to the value 0 (step S200), and this process ends.

[0024] If it is determined in step S120 that the notification history flag Frec is valued at 1 (there is a notification history), it is determined whether the absolute value of the battery 24's input limit Win is smaller than the absolute value of the control limit Winc (whether the input limit Win is larger than the control limit Winc) (step S140). If it is determined that the absolute value of the battery 24's input limit Win is smaller than the absolute value of the control limit Winc (the input limit Win is larger than the control limit Winc), a predetermined notification is made (step S150), the input limit Win is set to the control limit Winc (step S160), the processes from step S170 onward are executed, and this process is terminated.

[0025] If, in step S140, it is determined that the absolute value of the input limit Win of the battery 24 is greater than or equal to the absolute value of the control limit Winc (i.e., the input limit Win is less than or equal to the control limit Winc), the process from step S170 onward is executed without providing any predetermined notification, and this process is terminated.

[0026] Figure 3 is an explanatory diagram showing an example of the time changes of the predetermined notification, notification history flag Frec, regenerative torque Tm, and control limit Winc when the predetermined notification process of the embodiment is executed. The dashed line in the regenerative torque Tm column indicates the threshold Tref(SP), and the dashed line in the control limit Winc column indicates the input limit Win of the battery 24. When the regenerative torque Tm becomes greater than or equal to the threshold Tref(SP) at time T1, the predetermined notification is made for a certain period of time until time T2, the notification history flag Frec is set to a value of 1, and the input limit Win is set to the control limit Winc. When the regenerative torque Tm becomes greater than or equal to the threshold Tref(SP) again at time T3, since the notification history flag Frec is valued at 1, a determination is made as to whether the absolute value of the input limit Win of the battery 24 is less than the absolute value of the control limit Winc. However, since the input limit Win and the control limit Winc are the same, a negative determination is made, and the predetermined notification is not made again. From time T4 to time T5, upper limit protection is performed by the input limit Win of the control limit Winc. When the regenerative torque Tm exceeds the threshold Tref(SP) at time T6, the notification history flag Frec is set to value 1, so a determination is made as to whether the absolute value of the input limit Win of the battery 24 is smaller than the absolute value of the control limit Winc. Since the absolute value of the input limit Win is smaller than the absolute value of the control limit Winc, a positive determination is made, and the predetermined notification is given again until time T7, the notification history flag Frec is set to value 1, and the input limit Win is set as the control limit Winc.

[0027] In the electronic control unit 30 (on-board control device) installed in the electric vehicle 20 of the embodiment described above, when the regenerative torque Tm becomes greater than or equal to the threshold Tref(SP), a predetermined notification is given prompting the driver to press the brake pedal 47 for a certain period of time, and the notification history flag Frec is set to a value of 1, and the control limit Win is set to the input limit Win. Subsequently, when the regenerative torque Tm becomes greater than or equal to the threshold Tref(SP) while the notification history flag Frec is set to a value of 1, if the absolute value of the input limit Win of the battery 24 is less than the absolute value of the control limit Win, a predetermined notification is given prompting the driver to press the brake pedal 47 for a certain period of time. However, if the absolute value of the input limit Win of the battery 24 is greater than or equal to the absolute value of the control limit Win, the predetermined notification is not given. This makes it possible to suppress frequent notifications (predetermined notifications) prompting the driver to press the brake pedal 47 when the regenerative braking force decreases based on the state of the battery 24.

[0028] In the embodiment of the electric vehicle 20, a motor 22, an inverter 23, and a battery 24 are included, but any type of electric vehicle, such as a fuel cell vehicle or a hybrid vehicle, is acceptable as long as the battery is charged with power obtained by regenerating the motor.

[0029] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be explained. In the embodiment, the motor 22 corresponds to an "electric motor," the battery 24 corresponds to an "energy storage device," and the electronic control unit 30 corresponds to an "onboard control device."

[0030] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0031] Although the present disclosure has been described above using embodiments, the present disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of the present disclosure. [Industrial applicability]

[0032] This disclosure can be used in industries such as the manufacturing of in-vehicle control devices. [Explanation of Symbols]

[0033] 20 Electric vehicle, 22 Motor, 23 Inverter, 24 Battery, 25 Drive shaft, 26 Differential gear, 28a, 28b Drive wheels, 30 Electronic control unit, 42 Ignition switch, 43 Shift lever, 44 Shift position sensor, 45 Accelerator pedal, 46 Accelerator pedal position sensor, 47 Brake pedal, 48 Brake pedal position sensor, 49 Vehicle speed sensor, 50 Changeover switch, 52 Display device.

Claims

1. An on-board control device mounted on an electric vehicle, comprising an electric motor for propulsion and a power storage device that exchanges power with the electric motor, When the regenerative torque, which is a negative value obtained by the regenerative drive of the electric motor, reaches a predetermined threshold value, a predetermined notification is issued, and the fact that the predetermined notification was issued is recorded in the history, and the maximum allowable input power as a negative value that can be input to the energy storage device at the time the predetermined notification was issued is stored as the control input power. If there is a record of the predetermined notification being given, the predetermined notification is given again when the regenerative torque is equal to or greater than the predetermined threshold and the absolute value of the allowable maximum input power is less than the absolute value of the control input power. An in-vehicle control device characterized by the following features.

2. An in-vehicle control device according to claim 1, The control input power is protected by the upper limit of the allowable maximum input power. In-vehicle control device.

3. An in-vehicle control device according to claim 1 or 2, The predetermined threshold is set based on the shift position. In-vehicle control device.

4. A vehicle control device according to claim 1 or 2, The aforementioned predetermined notification is a notification that prompts the driver to apply the brakes. In-vehicle control device.

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